Asterotheca meriani (Brongn.) Stur and its spores from the Upper Triassic of Lunz (Austria)

Abstract

This paper deals with the morphological study of Asterotheca meriani (Brongn.) Stur, a species of ferns from the Upper Triassic of Lunz, Austria, well preserved in the form of carbonaceous crust on the shales. The frond is bipinnate. Pinnules are longer than broad and the venation is typically of Pecopteris type. Synangia are circular, borne intramarginally, comprising 4 sessile sporangia in close cohesion at the anterior end but slightly apart at the apical end. Spores are bilateral, circular to oval in polar view and indisputably show a longitudinal (monolete) slit, slightly bent in the middle. The spore exine is thick and finely granulose.